Question

SELECT * FROM training.dbo.[PERSON] P
LEFT JOIN training.dbo.PERSON_CAREER_HISTORY PC ON (P.PERSON_ID=PC.PERSON_ID)
CROSS JOIN (SELECT DISTINCT PC2.POSITION training.dbo.PERSON_CAREER_HISTORY) PC2 
WHERE PC.POSITION IS NULL

交叉连接部分无法发挥错误 “'。'附近的语法不正确。”

我无法解决它，并且已经修复了大约一个小时。请告诉我我的错误

Answer 1

您错过了FROM中的CROSS JOIN。

SELECT * FROM training.dbo.[PERSON] P
LEFT JOIN training.dbo.PERSON_CAREER_HISTORY PC ON (P.PERSON_ID=PC.PERSON_ID)
CROSS JOIN (SELECT DISTINCT PC2.POSITION FROM training.dbo.PERSON_CAREER_HISTORY) PC2 
WHERE PC.POSITION IS NULL

Answer 2

您错过了子查询中的FROM关键字。试试这个：

SELECT 
    * 
FROM 
    training.dbo.[PERSON] P
    LEFT JOIN training.dbo.PERSON_CAREER_HISTORY PC 
        ON (P.PERSON_ID=PC.PERSON_ID)
    CROSS JOIN (
        SELECT DISTINCT 
            PC2.POSITION 
        FROM
            training.dbo.PERSON_CAREER_HISTORY) PC2 
WHERE 
    PC.POSITION IS NULL

Answer 3

如果您正在寻找人们不所拥有的职位，那么这就是您想要的查询：

SELECT *
FROM training.dbo.[PERSON] P CROSS JOIN
     (SELECT DISTINCT PC2.POSITION FROM training.dbo.PERSON_CAREER_HISTORY
     ) pp LEFT JOIN
     training.dbo.PERSON_CAREER_HISTORY PCH
     ON P.PERSON_ID = PC.PERSON_ID AND pp.POSITION = PC.POSITION
WHERE PC.POSITION IS NULL;

join在您的版本中不正确（以及子查询的问题）。否则，我无法弄清楚原始查询的目的。

SQL：交叉连接查询

3 个答案: